SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8abd4cd0f7e39e5608938a14f337affe52666e93df0c357736e66f5cebacc649' 
  AND token = '3XA3WXlhx5uAM4GKZSRp8/PREiCPBpgaLCaSqSZNhKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}